Specialist teams have been searching the river and surrounding area.
Gillbanks said the woman’s death would be referred to the coroner.
The Independent Police Conduct Authority had been notified, “as is standard practice”.
“Police would like to thank our partner agencies, searchers, and the community for their efforts to return her to whānau.
“Our thoughts are with her whānau at this time,” Gillbanks said.
Earlier today, he said a 33-year-old man had been arrested in Gisborne.
The man had been charged with driving dangerously and failing to stop for police.
The Gisborne Herald reported Ashley William Forbes, 33, appeared in Gisborne District Court today.
He also faced several charges related to other alleged offending.
Forbes was remanded in custody until tomorrow afternoon for his next appearance.